The disclosure relates to a hydraulic block for a hydraulic power unit of a slip-controlled hydraulic vehicle brake system having the features of the disclosure.
Hydraulic blocks are known. These are typically low-profile cuboidal metal blocks for the installation of hydraulic components, such as hydraulic pumps, solenoid valves, hydraulic accumulators and damper chambers of a slip-controlled vehicle brake system. The hydraulic blocks hold the hydraulic components mechanically and connect them hydraulically, typically by means of bored connecting lines. A hydraulic block fitted with the hydraulic components forms a hydraulic power unit and is the heart of the slip control system. Low profile is intended to mean that hydraulic blocks often have a thickness which is approximately one quarter to one third and seldom more than half the length and width. In plan view, the hydraulic blocks are rectangular and are often almost square. Normally only hydraulic parts of the components are situated in the hydraulic block. Electromechanical parts, such as coils and armatures of the solenoid valves, project from the hydraulic blocks. An electric motor for driving the hydraulic pumps is likewise secured externally on the hydraulic block.
A hydraulic block of this kind is known from German Laid-Open Application DE 10 2006 059 924 A1. The known hydraulic block has receptacles for brake pressure buildup valves and for brake pressure reduction valves. The receptacles for the brake pressure buildup valves are arranged adjacent to one another in a row in the hydraulic block. The receptacles for the brake pressure reduction valves are arranged in the hydraulic block in another row parallel to the row of receptacles for the brake pressure buildup valves.
German Laid-Open Application DE 10 2009 054 985 A1 discloses a vehicle brake system which is suitable for “brake-by-wire” braking. “Brake-by-wire” refers to power braking of, for example, individual vehicle wheels to stabilize a motor vehicle in order to avoid skidding or to carry out braking for headway control. It is also possible to reduce a braking force, if required to zero. This occurs in electric vehicles or hybrid vehicles, for example, which are decelerated by operating an electric drive motor of the vehicle as a generator in order to recover kinetic energy of the motor vehicle during braking (“recuperation”). During a braking operation, the vehicle is decelerated partially or completely by operating the electric drive motor as a generator and otherwise by means of the vehicle brake system. In addition to the “brake-by-wire” mode, the known vehicle brake system can be operated by muscle power or power assistance.
For a brake pressure buildup for a “brake-by-wire” braking operation, the known vehicle brake system has a piston pump, the piston of which is moved by an electric motor by means of a screw mechanism.
Moreover, the known vehicle brake system has a pedal travel simulator to enable a pedal travel when the vehicle is being decelerated by operating an electric drive motor as a generator in order to recover energy. The pedal travel simulator is a piston-cylinder unit which, in the known vehicle brake system, is accommodated in a cylinder bore of a brake master cylinder in addition to the piston thereof. The piston-cylinder unit of the pedal travel simulator allows displacement of brake fluid and hence a pedal travel of a brake pedal without moving the piston or pistons of the brake master cylinder, i.e. without a brake pressure buildup. A simulator spring brings about a pedal force at the foot brake pedal in order to give a vehicle driver a pedal feel which is as normal as possible.
The brake master cylinder and, with it, the pedal travel simulator integrated therein and the piston pump for producing the brake pressure during a power braking operation are accommodated in a common housing in the known vehicle brake system.